TROBaseSuperChannel

Overview

This is the base abstract class for all super channels on the Delphi platform. Direct descendants of this class are TROBaseSuperTCPChannel and TROBaseSuperHTTPChannel. This class implements all common superchannel interfaces and implements or declares all common members.
Note: there are many class members missing descriptions because they are related to internal superchannel mechanics that users are unlikely to deal with.

Location


 

constructor Create  override

Standard component constructor

constructor Create(aOwner: TComponent)

Parameters:

  • aOwner: Owner

Active

Allows to get channel's activity state, whether the channel active i.e. attempts to connect or already connected. Allows to activate and deactivate the channel.

property Active: Boolean read write

Assign  override    (declared in TROTransportChannel)

Copies the contents of another, similar object.

procedure Assign(Source: TPersistent)

Parameters:

  • Source: Instance whose properties will be copied

AssignEvents  protected override

Copies the events of another, similar object.

procedure AssignEvents(aSource: TROTransportChannel)

Parameters:

  • aSource: Instance whose properties will be copied

AssignSpecificProperties  protected override

Copies the specific properties of another, similar object.

procedure AssignSpecificProperties(aSource: TROTransportChannel)

Parameters:

  • aSource: Instance whose properties will be copied

AsyncException  protected virtual    (declared in TROTransportChannel)

Notifies about an exception in an asynchronous mode.

procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)

Parameters:

  • aAsyncInterface: Exception source
  • AsyncException: Exception data

AutoReconnect  protected

Specifies whether to use auto reconnect feature if the specified server is not available.

property AutoReconnect: Boolean read write

AutoReconnectBehavior  protected

Controls the auto-reconnect behavior, if enabled. For possible auto-reconnect modes see TROSCAutoReconnectBehavior enum.

property AutoReconnectBehavior: TROSCAutoReconnectBehavior read write

BeforeDispatch  protected override

Allows an implimentation to do necessary preparatory actions (checking the readiness of the channel, restore session data, etc.).

procedure BeforeDispatch(aMessage: IROMessage)

Parameters:


Busy    (declared in TROTransportChannel)

Informs whether the channel is currently busy executing a remote request (true) or not (false). Most channels (except most notably the TROSuperTCPChannel) are only capable of performing one request at a time; if a second request is attempted while the channel is Busy, an EROChannelBusy exception will be raised.

property Busy: Boolean read

CallbackEvents  protected    (declared in TROBaseActiveEventChannel)

Sends event to each registered IROEventReceiver

procedure CallbackEvents(aData: TStream; aThread: TThread)

Parameters:

  • aData: Data stream
  • aThread: Working thread to process the event

ChangeServerLocator  protected override

procedure ChangeServerLocator(var aFaultStartLocatorIdx: Integer; var aRetry: Boolean; const aException: Exception)

Parameters:

  • aFaultStartLocatorIdx:
  • aRetry:
  • aException:

ChannelMatchingTargetUri    (declared in TROTransportChannel)

Creates a client channel instance with type, target host and target port matching the provided target Uri.
F.e. for provided uri supertcp://192.168.1.100:7020/bin this method will return an instance of the Super Tcp channel with target host set to 192.168.1.100 and port set to 7020.

class function ChannelMatchingTargetUri(const aUri: TROUri): TROTransportChannel

Parameters:

  • aUri: Server Uri

ChannelMatchingTargetUrl    (declared in TROTransportChannel)

class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel

Parameters:

  • aUrl:

CheckProperties  virtual    (declared in TROTransportChannel)

Validates channel properties

procedure CheckProperties

CheckStatus  protected

Indicates whether an answer is received after an InvokeRequest.

function CheckStatus(const aMessageID: string): Boolean

Parameters:

  • aMessageID: Value of the previously called InvokeRequest result

ClientId  protected

The unique identifier of the client and it's session on the server. See TROMessage description for more details. The property is assigned automatically during the process of data exchange between the client and the server.

property ClientId: TGUID read write

Connected

Returns true if the channel is connected to the server.

property Connected: Boolean read

ConnectEvent

property ConnectEvent: TROEvent read

ConnectionWaitTimeout  protected

The timeout to establish connection to the server. Expressed in milliseconds, the default value is 10000 (10 sec).

property ConnectionWaitTimeout: Integer read write

ConnectTimeout

Connection timeout

property ConnectTimeout: Integer read write

CreateWorkerThread  protected virtual abstract

function CreateWorkerThread: TThread

CurrentLocator    (declared in TROTransportChannel)

Returns which of the fail-over/load balancing servers configured in the ServerLocators is currently active. Depending on the DispatchOptions defined, this value might change with each request, or only if the current server fails.

property CurrentLocator: TROServerLocator read write

DecryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

Decrypt stream

procedure DecryptStream(const Source: TStream; const Dest: TStream)

Parameters:

  • Source: Source
  • Dest: Destination

DecryptStream (TStream)  protected overload    (declared in TROBaseConnection)

Decrypt stream

procedure DecryptStream(const Stream: TStream)

Parameters:

  • Stream: Stream

Dispatch (IROMessage)  protected reintroduce overload    (declared in TROTransportChannel)

Sends a request message through the Self channel for processing and gets back an aMessage. CodeGen uses this method when generating a proxy from RODL Files.

procedure Dispatch(aMessage: IROMessage)

Parameters:

  • aMessage: (In/out) message data

DispatchOptions

Configures the available fail-over and load balancing options provided by the Remoting SDK. By default, channels are set up to talk to one specific server only. Two independent options are available to provide fail-over and load balancing:

  • Enables fail-over support. If the connection to any given server fails, the channel will automatically keep trying the next server specified in ServerLocators, until a working server is found or all servers have been tried.
  • Enables load-balancing support. Each request dispatched through the channel will go to a different server configured in ServerLocators, resulting in calls being more or less equally distributed over the available servers.

Enabling any of these options obviously requires the server to be implemented in a stateless way, so that it does not depend on all requests from a client going to the same server. This implies using a class factory different from Per-Client and, if sessions are used, a session manager that allows sharing of session state between servers.

property DispatchOptions: TRODispatchOptions read write

DoAfterProbingServerEvent  protected override

Fires OnAfterProbingServer event

procedure DoAfterProbingServerEvent(const aServerLocator: TROServerLocator; const aFailed: Boolean)

Parameters:

  • aServerLocator: Server locator
  • aFailed:

DoAfterProbingServersEvent  protected override

Fires OnAfterProbingServer event

procedure DoAfterProbingServersEvent(const aProbedCount: Integer; const aEnabledCount: Integer; const aDisabledCount: Integer)

Parameters:

  • aProbedCount:
  • aEnabledCount:
  • aDisabledCount:

DoBeforeDecryptEvent  protected virtual    (declared in TROBaseConnection) obsolete

procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)

Parameters:

  • aEncryptedStream: Stream

DoBeforeProbingServerEvent  protected override

Fires OnBeforeProbingServer event

procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)

Parameters:

  • aServerLocator: Server locator

DoBeforeProbingServersEvent  protected override

Fires OnBeforeProbingServers event

procedure DoBeforeProbingServersEvent

DoNeedSSL  protected virtual    (declared in TROTransportChannel)

Detects SSL state

function DoNeedSSL: Boolean

DoProcessError  protected

function DoProcessError(const aId: Integer; const aErrorNo: Integer): Boolean

Parameters:

  • aId:
  • aErrorNo:

DoReceiveStreamEvent  protected override

Fires OnSendStream event

procedure DoReceiveStreamEvent(const Dest: TStream)

Parameters:

  • Dest: Stream

DoReconnect  protected

procedure DoReconnect(var aRestartLoop: Boolean)

Parameters:

  • aRestartLoop:

DoSendStreamEvent  protected override

Fires OnSendStream event

procedure DoSendStreamEvent(const Source: TStream)

Parameters:

  • Source: Stream

DoServerLocatorAssignmentEvent  protected override

Fires OnServerLocatorAssignment event

procedure DoServerLocatorAssignmentEvent(const aLocator: TROServerLocator; const aException: Exception)

Parameters:

  • aLocator:
  • aException:

Encryption    (declared in TROBaseConnection) obsolete

This is DES based enscryption, it is obsolete because works only for Delphi. Use message envelope AES Encryption Envelope instead.

property Encryption: TROEncryption read write

EncryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

Encrypt stream

procedure EncryptStream(const Source: TStream; const Dest: TStream)

Parameters:

  • Source: Source
  • Dest: Destination

EncryptStream (TStream)  protected overload    (declared in TROBaseConnection)

Encrypt stream

procedure EncryptStream(const Stream: TStream)

Parameters:

  • Stream: Stream

EventReceiverList  protected    (declared in TROBaseActiveEventChannel)

Provides a list of registered IROEventReceiver

property EventReceiverList: TInterfaceList read

EventThreadPool

Refers to the TROThreadPool instance to provide a thread pool to execute event handling routines on. If the thread pool is not set explicitly it is created autromatically upon access.

property EventThreadPool: TROThreadPool read write

FaultToleranceLocatorIdx    (declared in TROTransportChannel)

property FaultToleranceLocatorIdx: Integer read write

FindWaitingRequest  protected

function FindWaitingRequest(aList: TList<TROWaitingRequest>; aId: Integer): TROWaitingRequest

Parameters:

  • aList:
  • aId:

GetBusy  protected virtual    (declared in TROTransportChannel)

Returns current channel state

function GetBusy: Boolean

GetChannelFromPool  protected virtual    (declared in TROTransportChannel)

function GetChannelFromPool: TROTransportChannel

GetStrippedTargetUrl  protected virtual

function GetStrippedTargetUrl: string

GetTransportObject  protected virtual    (declared in TROTransportChannel)

Returns itself.

function GetTransportObject: TObject

HasData  protected

This method is called when incoming data is present.

procedure HasData(aId: Integer; aData: TStream)

Parameters:

  • aId:
  • aData:

InDestroyingState  protected

Returns current state

function InDestroyingState: Boolean

InitialConnect  protected

function InitialConnect: Boolean

InitServerLocator  protected override

Sets CurrentLocator

function InitServerLocator: Integer

InitWorkerThread  protected

procedure InitWorkerThread

InvokeRequest  protected

Indicates whether an answer is received after an InvokeRequest.

function InvokeRequest(aRequest: TStream; aGetResponse: Boolean): string

Parameters:

  • aRequest: Id of a waiting response
  • aGetResponse: Response data

IsEncryptionUsed  protected    (declared in TROBaseConnection)

Checks if encryption was used

function IsEncryptionUsed: Boolean

IsProbeMode  protected    (declared in TROTransportChannel)

property IsProbeMode: Boolean read

IsStreamEncrypted  protected    (declared in TROBaseConnection)

Checks state of stream

function IsStreamEncrypted(Source: TStream): Boolean

Parameters:

  • Source: Stream

LaunchAsyncTask  protected    (declared in TROTransportChannel)

procedure LaunchAsyncTask(aRequest: IROAsyncRequest)

Parameters:

  • aRequest:

LoadBalancerLocatorIdx    (declared in TROTransportChannel)

property LoadBalancerLocatorIdx: Integer read write

LoadSSL  protected virtual    (declared in TROTransportChannel)

Loads SSL library if SSL protocol is used

procedure LoadSSL

MaxPackageSize

Sets the maximum size for data packages that the channel will transport (default is 10485760, 10 MB).

property MaxPackageSize: Integer read write

Notification  protected override

Forwards notification messages to all owned components.

procedure Notification(AComponent: TComponent; Operation: TOperation)

Parameters:

  • AComponent: component
  • Operation: operation

OnAfterEncrypt    (declared in TROBaseConnection)

Fired after stream was encrypted

property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnAfterProbingServer

Fires after the channel is done probing a specific server for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServer: TROEndProbeServerEvent read write

OnAfterProbingServers

Fires after the channel is done probing all servers for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServers: TROEndProbeServersEvent read write

OnAsyncException    (declared in TROTransportChannel)

Fires when exception is raised in asynchronous mode

property OnAsyncException: TROAsyncExceptionEvent read write
delegate: procedure OnAsyncException(Sender: TROTransportChannel; Async: IROAsyncInterface; anException: Exception)

OnBeforeDecrypt    (declared in TROBaseConnection)

Fired before stream will be decrypted

property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnBeforeProbingServer

Fires before the channel starts probing a specific server for availability. You can use this event to:

property OnBeforeProbingServer: TROBeginProbeServerEvent read write

OnBeforeProbingServers

Fires before the channel starts probing all servers for availability. You can use this event:

  • to check or adjust the server configurations
  • to include/exclude individual server from being probed by changing their TROServerLocator properties.
property OnBeforeProbingServers: TROBeginProbeServersEvent read write

OnConnected

Fires when channel is connected to server

property OnConnected: TNotifyEvent read write

OnDisconnected

Fires when the active connection to the server has been dropped or lost.

property OnDisconnected: TNotifyEvent read write

OnException    (declared in TROTransportChannel)

Fires if an exception is raised during the execution of a remote request. This could be an exception returned from the server, a communication problem or an error within the client. Depending on the type of error, your event handler can try to rectify the problem, and set aRetry to true to have the channel try and perform the request again. For example, an application could show a dialog asking the user to confirm if his internet connection is available, with Cancel and Retry buttons.
If aRetry is set to true and the call succeeds at the second attempt, the call will return to the original code that initiated the request, as if the exception never happened.

property OnException: TROExceptionEvent read write
delegate: procedure OnException(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)

OnLoginNeeded

Fires if an EROSessionNotFound (or the descendant SessionNotFoundException) exception is raised during the execution of a remote request. This usually indicates that the server cannot authenticate the client or that the session has expired. The most common use for this event is to perform a call to a special Login service provided by the server (possibly after prompting the user to enter username and password), and to set the aRetry parameter to true if login was successful.

property OnLoginNeeded: TROExceptionEvent read write

OnProgress

This event fires as the channel is transferring data for a request or response to or from the server, informing of the current progress. It can be used to keep the user interface updated during lengthy transfers,e.g. by showing a progress bar or the remaining transfer volume. Note: the accuracy and frequency of calls to OnProgress depends on the channel type; since channels transport data packets in different sized chunks (or even all-at-once), OnProgress might show a very fine progress for some channels, while jumping from 0 to 100% in one step with others.

property OnProgress: TProgressEvent read write

OnReceiveStream

Fires after a stream with a response message has been received from the server. Use this event handler to inspect and possibly modify the stream, before it continues to be processed by the higher levels of the Remoting SDK framework.

property OnReceiveStream: TStreamDispatch read write

OnSendStream

Fires just as a stream with a request message will be sent to the server. The event handler can inspect and possibly modify the stream, before it continues to be sent off to the server.

property OnSendStream: TStreamDispatch read write

OnServerLocatorAssignment

Fires before changing of a server locator.

property OnServerLocatorAssignment: TServerLocatorAssignment read write

Probe  protected    (declared in TROTransportChannel)

Checks the accessibility of servers from the ServerLocators. This method is intended to provide fail-over and load balancing support in the Remoting SDK Architecture.

function Probe(aServerLocator: TROServerLocator): Boolean

Parameters:

  • aServerLocator: Server locator

ProbeAll  protected    (declared in TROTransportChannel)

Checks the availability of all known servers.

procedure ProbeAll

ProbeFrequency

Sets at what intervals, in milliseconds, the channel will probe the servers configured in ServerLocators for availability. The default value is 60,000 (60 seconds). See the ProbeServers property for a more detailed description. Although somewhat misnamed, this property defines the Interval between probes, not the actual probing Frequency. The property name is persisted for backward compatibility.

property ProbeFrequency: Cardinal read write

ProbeServers

Toggles whether the channel will continuously probe the servers configured in ServerLocators for availability. If enabled (true), the channel will ping all servers at a regular interval to determine if they are reachable. If a server fails to respond, it will be disabled for future calls until a later probe can reach it again. The interval between probes can be configured using the ProbeFrequency property. By default, server probing is turned off.

property ProbeServers: Boolean read write

ProcessEvent  protected

procedure ProcessEvent(aData: TStream)

Parameters:

  • aData:

ReconnectDelay  protected

The time interval to pass between reconnect attempts, in millisecnds. The default is 500 (0.5 second).

property ReconnectDelay: Integer read write

ReconnectEvent

property ReconnectEvent: TROEvent read

RegisterEventReceiver  protected virtual    (declared in TROBaseActiveEventChannel)

Registers a new event receiver object aReceiver in the specified channel. This procedure is needed to further use the aReceiver as receiver for callback events.

procedure RegisterEventReceiver(aReceiver: IROEventReceiver)

Parameters:

  • aReceiver: the event receiver that should be registered.

RequestTimeout

The timeout to complete the remote request on the server. Expressed in milliseconds, the default value is 60000 (60 sec). All requests that last longer than the timeout specified are considered failed.

property RequestTimeout: Integer read write

ResetProbingClone  protected override

Resets channel that is used for probing

procedure ResetProbingClone(aProbe: TROTransportChannel)

Parameters:

  • aProbe: Probing clone

RetrieveMetadata  protected virtual    (declared in TROTransportChannel)

Returns server-side RODL.

procedure RetrieveMetadata(out Dest: TStream)

Parameters:

  • Dest: Stream

RetrieveResponse  protected

Indicates whether an answer is received after an InvokeRequest.

procedure RetrieveResponse(const aMessageID: string; aResponse: TStream)

Parameters:

  • aMessageID: Id of a waiting response
  • aResponse: Response data

RetrieveRODL  protected    (declared in TROTransportChannel)

This method is used for to obtaining the RODL library from the server without havin to rely on a channel-specific mechanism (such as a HTTP request to http://servername:port/rodl).

procedure RetrieveRODL(out RODLLibrary: TRODLLibrary)

Parameters:

  • RODLLibrary: Result

ReturnChannelToPool  protected virtual    (declared in TROTransportChannel)

procedure ReturnChannelToPool(aChannel: TROTransportChannel)

Parameters:

  • aChannel:

ROActiveAsyncTransportChannel_InvokeRequest (TStream, Boolean, TROEvent): string  protected overload virtual abstract

function ROActiveAsyncTransportChannel_InvokeRequest(aRequest: TStream; aGetResponse: Boolean; aEvent: TROEvent): string

Parameters:

  • aRequest:
  • aGetResponse:
  • aEvent:

ROFreeNotification    (declared in TROComponent)

Forwards notification messages to all owned components.

procedure ROFreeNotification(aComponent: TComponent)

Parameters:

  • aComponent: component

RORemoveFreeNotification    (declared in TROComponent)

Forwards notification messages to all owned components.

procedure RORemoveFreeNotification(aComponent: TComponent)

Parameters:

  • aComponent: component

SendRemoveNotification  protected    (declared in TROComponent)

Forwards notification messages to all owned components.

procedure SendRemoveNotification(aComponent: TComponent)

Parameters:

  • aComponent: component

ServerLocators

Optionally, this collection property can be filled to contain a list of possible servers to be used for fail-over or load balancing purposes. Depending on the settings configured in DispatchOptions, the channel will automatically spread calls over the available servers, or fall back to another server if one fails.

property ServerLocators: TROServerLocatorCollection read write

SessionId  protected

The unique identifier of the current session on the server. The same as ClientId.

property SessionId: TGUID read write

SetAsyncBusy  protected override

procedure SetAsyncBusy(const Value: Boolean)

Parameters:

  • Value:

SetConnectedState  protected

procedure SetConnectedState

SetInactive  protected virtual

procedure SetInactive

SetServerLocator  protected    (declared in TROTransportChannel)

Retrieves the location details of a server from aServerLocator.

procedure SetServerLocator(aServerLocator: TROServerLocator; anException: Exception)

Parameters:

  • aServerLocator: Configuration data of the server
  • anException: Exception

StoreActive

Controls whether the Active property value is stored in the dfm file.

property StoreActive: Boolean read write

SuperChannel_RaiseError  protected virtual abstract

procedure SuperChannel_RaiseError(aCode: Integer)

Parameters:

  • aCode:

SynchronizedProbing

Determines whether server probing happens in the context of the main VCL thread (true, default) or in a background worker thread. See the ProbeServers property for a more detailed description.

property SynchronizedProbing: Boolean read write

SynchronizeEvents

According to the superchannel nature every remote request is processed using it's own background thread. This property controls on which thread to execute the event handlers for events connected with each remote request. If the property is set to true than all event handlers are executed on the main application thread, otherwise they are executed on the request's background thread.
WARNING: This property has no effect on OnSendStream and OnReceiveStream events, they are always executed in main thread.

property SynchronizeEvents: Boolean read write

TargetUri    (declared in TROTransportChannel)

Target URI

property TargetUri: TROUri read write

TargetUrl

The address of the server.

property TargetUrl: string read write

TerminateWorkerThread  protected

procedure TerminateWorkerThread

ThreadSafe  protected    (declared in TROTransportChannel)

property ThreadSafe: Boolean read write

TriggerProgress  protected override

Fires OnProgress event

procedure TriggerProgress(aType: TProgressType; aDirection: TProgressDirection; aTransfered: Integer; aTotal: Integer)

Parameters:

  • aType: progress type
  • aDirection: direction
  • aTransfered: transfered bytes
  • aTotal: total bytes

UnregisterEventReceiver  protected virtual    (declared in TROBaseActiveEventChannel)

Unregisters the specified IROEventReceiver aReceiver in the specified channel.

procedure UnregisterEventReceiver(aReceiver: IROEventReceiver)

Parameters:

  • aReceiver: The event receiver that should be unregistered.

UnregisterEventReceivers  protected    (declared in TROBaseActiveEventChannel)

Unregisters the all event receivers in the specified channel.

procedure UnregisterEventReceivers

WaitForActive

procedure WaitForActive(const aTimeout: Integer)

Parameters:

  • aTimeout:

WaitingRequests  protected

Internal storage of remote requests awaiting for response.

property WaitingRequests: TThreadList<TROWaitingRequest> read

WorkerThread  protected

Internal background threads management property.

property WorkerThread: TThread read

 

Active

Allows to get channel's activity state, whether the channel active i.e. attempts to connect or already connected. Allows to activate and deactivate the channel.

property Active: Boolean read write

AutoReconnect  protected

Specifies whether to use auto reconnect feature if the specified server is not available.

property AutoReconnect: Boolean read write

AutoReconnectBehavior  protected

Controls the auto-reconnect behavior, if enabled. For possible auto-reconnect modes see TROSCAutoReconnectBehavior enum.

property AutoReconnectBehavior: TROSCAutoReconnectBehavior read write

Busy    (declared in TROTransportChannel)

Informs whether the channel is currently busy executing a remote request (true) or not (false). Most channels (except most notably the TROSuperTCPChannel) are only capable of performing one request at a time; if a second request is attempted while the channel is Busy, an EROChannelBusy exception will be raised.

property Busy: Boolean read

ClientId  protected

The unique identifier of the client and it's session on the server. See TROMessage description for more details. The property is assigned automatically during the process of data exchange between the client and the server.

property ClientId: TGUID read write

Connected

Returns true if the channel is connected to the server.

property Connected: Boolean read

ConnectionWaitTimeout  protected

The timeout to establish connection to the server. Expressed in milliseconds, the default value is 10000 (10 sec).

property ConnectionWaitTimeout: Integer read write

ConnectTimeout

Connection timeout

property ConnectTimeout: Integer read write

CurrentLocator    (declared in TROTransportChannel)

Returns which of the fail-over/load balancing servers configured in the ServerLocators is currently active. Depending on the DispatchOptions defined, this value might change with each request, or only if the current server fails.

property CurrentLocator: TROServerLocator read write

DispatchOptions

Configures the available fail-over and load balancing options provided by the Remoting SDK. By default, channels are set up to talk to one specific server only. Two independent options are available to provide fail-over and load balancing:

  • Enables fail-over support. If the connection to any given server fails, the channel will automatically keep trying the next server specified in ServerLocators, until a working server is found or all servers have been tried.
  • Enables load-balancing support. Each request dispatched through the channel will go to a different server configured in ServerLocators, resulting in calls being more or less equally distributed over the available servers.

Enabling any of these options obviously requires the server to be implemented in a stateless way, so that it does not depend on all requests from a client going to the same server. This implies using a class factory different from Per-Client and, if sessions are used, a session manager that allows sharing of session state between servers.

property DispatchOptions: TRODispatchOptions read write

Encryption    (declared in TROBaseConnection) obsolete

This is DES based enscryption, it is obsolete because works only for Delphi. Use message envelope AES Encryption Envelope instead.

property Encryption: TROEncryption read write

EventReceiverList  protected    (declared in TROBaseActiveEventChannel)

Provides a list of registered IROEventReceiver

property EventReceiverList: TInterfaceList read

EventThreadPool

Refers to the TROThreadPool instance to provide a thread pool to execute event handling routines on. If the thread pool is not set explicitly it is created autromatically upon access.

property EventThreadPool: TROThreadPool read write

FaultToleranceLocatorIdx    (declared in TROTransportChannel)

property FaultToleranceLocatorIdx: Integer read write

IsProbeMode  protected    (declared in TROTransportChannel)

property IsProbeMode: Boolean read

LoadBalancerLocatorIdx    (declared in TROTransportChannel)

property LoadBalancerLocatorIdx: Integer read write

MaxPackageSize

Sets the maximum size for data packages that the channel will transport (default is 10485760, 10 MB).

property MaxPackageSize: Integer read write

OnAfterProbingServer

Fires after the channel is done probing a specific server for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServer: TROEndProbeServerEvent read write

OnAfterProbingServers

Fires after the channel is done probing all servers for availability. You can use this event to check the result of the probing, possibly to update internal data structures or to display server status in the user interface.

property OnAfterProbingServers: TROEndProbeServersEvent read write

OnBeforeProbingServer

Fires before the channel starts probing a specific server for availability. You can use this event to:

property OnBeforeProbingServer: TROBeginProbeServerEvent read write

OnBeforeProbingServers

Fires before the channel starts probing all servers for availability. You can use this event:

  • to check or adjust the server configurations
  • to include/exclude individual server from being probed by changing their TROServerLocator properties.
property OnBeforeProbingServers: TROBeginProbeServersEvent read write

OnLoginNeeded

Fires if an EROSessionNotFound (or the descendant SessionNotFoundException) exception is raised during the execution of a remote request. This usually indicates that the server cannot authenticate the client or that the session has expired. The most common use for this event is to perform a call to a special Login service provided by the server (possibly after prompting the user to enter username and password), and to set the aRetry parameter to true if login was successful.

property OnLoginNeeded: TROExceptionEvent read write

OnProgress

This event fires as the channel is transferring data for a request or response to or from the server, informing of the current progress. It can be used to keep the user interface updated during lengthy transfers,e.g. by showing a progress bar or the remaining transfer volume. Note: the accuracy and frequency of calls to OnProgress depends on the channel type; since channels transport data packets in different sized chunks (or even all-at-once), OnProgress might show a very fine progress for some channels, while jumping from 0 to 100% in one step with others.

property OnProgress: TProgressEvent read write

OnReceiveStream

Fires after a stream with a response message has been received from the server. Use this event handler to inspect and possibly modify the stream, before it continues to be processed by the higher levels of the Remoting SDK framework.

property OnReceiveStream: TStreamDispatch read write

OnSendStream

Fires just as a stream with a request message will be sent to the server. The event handler can inspect and possibly modify the stream, before it continues to be sent off to the server.

property OnSendStream: TStreamDispatch read write

OnServerLocatorAssignment

Fires before changing of a server locator.

property OnServerLocatorAssignment: TServerLocatorAssignment read write

ProbeFrequency

Sets at what intervals, in milliseconds, the channel will probe the servers configured in ServerLocators for availability. The default value is 60,000 (60 seconds). See the ProbeServers property for a more detailed description. Although somewhat misnamed, this property defines the Interval between probes, not the actual probing Frequency. The property name is persisted for backward compatibility.

property ProbeFrequency: Cardinal read write

ProbeServers

Toggles whether the channel will continuously probe the servers configured in ServerLocators for availability. If enabled (true), the channel will ping all servers at a regular interval to determine if they are reachable. If a server fails to respond, it will be disabled for future calls until a later probe can reach it again. The interval between probes can be configured using the ProbeFrequency property. By default, server probing is turned off.

property ProbeServers: Boolean read write

ReconnectDelay  protected

The time interval to pass between reconnect attempts, in millisecnds. The default is 500 (0.5 second).

property ReconnectDelay: Integer read write

RequestTimeout

The timeout to complete the remote request on the server. Expressed in milliseconds, the default value is 60000 (60 sec). All requests that last longer than the timeout specified are considered failed.

property RequestTimeout: Integer read write

ServerLocators

Optionally, this collection property can be filled to contain a list of possible servers to be used for fail-over or load balancing purposes. Depending on the settings configured in DispatchOptions, the channel will automatically spread calls over the available servers, or fall back to another server if one fails.

property ServerLocators: TROServerLocatorCollection read write

SessionId  protected

The unique identifier of the current session on the server. The same as ClientId.

property SessionId: TGUID read write

StoreActive

Controls whether the Active property value is stored in the dfm file.

property StoreActive: Boolean read write

SynchronizedProbing

Determines whether server probing happens in the context of the main VCL thread (true, default) or in a background worker thread. See the ProbeServers property for a more detailed description.

property SynchronizedProbing: Boolean read write

SynchronizeEvents

According to the superchannel nature every remote request is processed using it's own background thread. This property controls on which thread to execute the event handlers for events connected with each remote request. If the property is set to true than all event handlers are executed on the main application thread, otherwise they are executed on the request's background thread.
WARNING: This property has no effect on OnSendStream and OnReceiveStream events, they are always executed in main thread.

property SynchronizeEvents: Boolean read write

TargetUri    (declared in TROTransportChannel)

Target URI

property TargetUri: TROUri read write

TargetUrl

The address of the server.

property TargetUrl: string read write

ThreadSafe  protected    (declared in TROTransportChannel)

property ThreadSafe: Boolean read write

WaitingRequests  protected

Internal storage of remote requests awaiting for response.

property WaitingRequests: TThreadList<TROWaitingRequest> read

WorkerThread  protected

Internal background threads management property.

property WorkerThread: TThread read

 

ChannelMatchingTargetUri    (declared in TROTransportChannel)

Creates a client channel instance with type, target host and target port matching the provided target Uri.
F.e. for provided uri supertcp://192.168.1.100:7020/bin this method will return an instance of the Super Tcp channel with target host set to 192.168.1.100 and port set to 7020.

class function ChannelMatchingTargetUri(const aUri: TROUri): TROTransportChannel

Parameters:

  • aUri: Server Uri

ChannelMatchingTargetUrl    (declared in TROTransportChannel)

class function ChannelMatchingTargetUrl(const aUrl: string): TROTransportChannel

Parameters:

  • aUrl:

 

constructor Create  override

Standard component constructor

constructor Create(aOwner: TComponent)

Parameters:

  • aOwner: Owner

Assign  override    (declared in TROTransportChannel)

Copies the contents of another, similar object.

procedure Assign(Source: TPersistent)

Parameters:

  • Source: Instance whose properties will be copied

AssignEvents  protected override

Copies the events of another, similar object.

procedure AssignEvents(aSource: TROTransportChannel)

Parameters:

  • aSource: Instance whose properties will be copied

AssignSpecificProperties  protected override

Copies the specific properties of another, similar object.

procedure AssignSpecificProperties(aSource: TROTransportChannel)

Parameters:

  • aSource: Instance whose properties will be copied

AsyncException  protected virtual    (declared in TROTransportChannel)

Notifies about an exception in an asynchronous mode.

procedure AsyncException(aAsyncInterface: IROAsyncInterface; AsyncException: Exception)

Parameters:

  • aAsyncInterface: Exception source
  • AsyncException: Exception data

BeforeDispatch  protected override

Allows an implimentation to do necessary preparatory actions (checking the readiness of the channel, restore session data, etc.).

procedure BeforeDispatch(aMessage: IROMessage)

Parameters:


CallbackEvents  protected    (declared in TROBaseActiveEventChannel)

Sends event to each registered IROEventReceiver

procedure CallbackEvents(aData: TStream; aThread: TThread)

Parameters:

  • aData: Data stream
  • aThread: Working thread to process the event

ChangeServerLocator  protected override

procedure ChangeServerLocator(var aFaultStartLocatorIdx: Integer; var aRetry: Boolean; const aException: Exception)

Parameters:

  • aFaultStartLocatorIdx:
  • aRetry:
  • aException:

CheckProperties  virtual    (declared in TROTransportChannel)

Validates channel properties

procedure CheckProperties

CheckStatus  protected

Indicates whether an answer is received after an InvokeRequest.

function CheckStatus(const aMessageID: string): Boolean

Parameters:

  • aMessageID: Value of the previously called InvokeRequest result

CreateWorkerThread  protected virtual abstract

function CreateWorkerThread: TThread

DecryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

Decrypt stream

procedure DecryptStream(const Source: TStream; const Dest: TStream)

Parameters:

  • Source: Source
  • Dest: Destination

DecryptStream (TStream)  protected overload    (declared in TROBaseConnection)

Decrypt stream

procedure DecryptStream(const Stream: TStream)

Parameters:

  • Stream: Stream

Dispatch (IROMessage)  protected reintroduce overload    (declared in TROTransportChannel)

Sends a request message through the Self channel for processing and gets back an aMessage. CodeGen uses this method when generating a proxy from RODL Files.

procedure Dispatch(aMessage: IROMessage)

Parameters:

  • aMessage: (In/out) message data

DoAfterProbingServerEvent  protected override

Fires OnAfterProbingServer event

procedure DoAfterProbingServerEvent(const aServerLocator: TROServerLocator; const aFailed: Boolean)

Parameters:

  • aServerLocator: Server locator
  • aFailed:

DoAfterProbingServersEvent  protected override

Fires OnAfterProbingServer event

procedure DoAfterProbingServersEvent(const aProbedCount: Integer; const aEnabledCount: Integer; const aDisabledCount: Integer)

Parameters:

  • aProbedCount:
  • aEnabledCount:
  • aDisabledCount:

DoBeforeDecryptEvent  protected virtual    (declared in TROBaseConnection) obsolete

procedure DoBeforeDecryptEvent(aEncryptedStream: TStream)

Parameters:

  • aEncryptedStream: Stream

DoBeforeProbingServerEvent  protected override

Fires OnBeforeProbingServer event

procedure DoBeforeProbingServerEvent(const aServerLocator: TROServerLocator)

Parameters:

  • aServerLocator: Server locator

DoBeforeProbingServersEvent  protected override

Fires OnBeforeProbingServers event

procedure DoBeforeProbingServersEvent

DoNeedSSL  protected virtual    (declared in TROTransportChannel)

Detects SSL state

function DoNeedSSL: Boolean

DoProcessError  protected

function DoProcessError(const aId: Integer; const aErrorNo: Integer): Boolean

Parameters:

  • aId:
  • aErrorNo:

DoReceiveStreamEvent  protected override

Fires OnSendStream event

procedure DoReceiveStreamEvent(const Dest: TStream)

Parameters:

  • Dest: Stream

DoReconnect  protected

procedure DoReconnect(var aRestartLoop: Boolean)

Parameters:

  • aRestartLoop:

DoSendStreamEvent  protected override

Fires OnSendStream event

procedure DoSendStreamEvent(const Source: TStream)

Parameters:

  • Source: Stream

DoServerLocatorAssignmentEvent  protected override

Fires OnServerLocatorAssignment event

procedure DoServerLocatorAssignmentEvent(const aLocator: TROServerLocator; const aException: Exception)

Parameters:

  • aLocator:
  • aException:

EncryptStream (TStream, TStream)  protected overload    (declared in TROBaseConnection)

Encrypt stream

procedure EncryptStream(const Source: TStream; const Dest: TStream)

Parameters:

  • Source: Source
  • Dest: Destination

EncryptStream (TStream)  protected overload    (declared in TROBaseConnection)

Encrypt stream

procedure EncryptStream(const Stream: TStream)

Parameters:

  • Stream: Stream

FindWaitingRequest  protected

function FindWaitingRequest(aList: TList<TROWaitingRequest>; aId: Integer): TROWaitingRequest

Parameters:

  • aList:
  • aId:

GetBusy  protected virtual    (declared in TROTransportChannel)

Returns current channel state

function GetBusy: Boolean

GetChannelFromPool  protected virtual    (declared in TROTransportChannel)

function GetChannelFromPool: TROTransportChannel

GetStrippedTargetUrl  protected virtual

function GetStrippedTargetUrl: string

GetTransportObject  protected virtual    (declared in TROTransportChannel)

Returns itself.

function GetTransportObject: TObject

HasData  protected

This method is called when incoming data is present.

procedure HasData(aId: Integer; aData: TStream)

Parameters:

  • aId:
  • aData:

InDestroyingState  protected

Returns current state

function InDestroyingState: Boolean

InitialConnect  protected

function InitialConnect: Boolean

InitServerLocator  protected override

Sets CurrentLocator

function InitServerLocator: Integer

InitWorkerThread  protected

procedure InitWorkerThread

InvokeRequest  protected

Indicates whether an answer is received after an InvokeRequest.

function InvokeRequest(aRequest: TStream; aGetResponse: Boolean): string

Parameters:

  • aRequest: Id of a waiting response
  • aGetResponse: Response data

IsEncryptionUsed  protected    (declared in TROBaseConnection)

Checks if encryption was used

function IsEncryptionUsed: Boolean

IsStreamEncrypted  protected    (declared in TROBaseConnection)

Checks state of stream

function IsStreamEncrypted(Source: TStream): Boolean

Parameters:

  • Source: Stream

LaunchAsyncTask  protected    (declared in TROTransportChannel)

procedure LaunchAsyncTask(aRequest: IROAsyncRequest)

Parameters:

  • aRequest:

LoadSSL  protected virtual    (declared in TROTransportChannel)

Loads SSL library if SSL protocol is used

procedure LoadSSL

Notification  protected override

Forwards notification messages to all owned components.

procedure Notification(AComponent: TComponent; Operation: TOperation)

Parameters:

  • AComponent: component
  • Operation: operation

Probe  protected    (declared in TROTransportChannel)

Checks the accessibility of servers from the ServerLocators. This method is intended to provide fail-over and load balancing support in the Remoting SDK Architecture.

function Probe(aServerLocator: TROServerLocator): Boolean

Parameters:

  • aServerLocator: Server locator

ProbeAll  protected    (declared in TROTransportChannel)

Checks the availability of all known servers.

procedure ProbeAll

ProcessEvent  protected

procedure ProcessEvent(aData: TStream)

Parameters:

  • aData:

RegisterEventReceiver  protected virtual    (declared in TROBaseActiveEventChannel)

Registers a new event receiver object aReceiver in the specified channel. This procedure is needed to further use the aReceiver as receiver for callback events.

procedure RegisterEventReceiver(aReceiver: IROEventReceiver)

Parameters:

  • aReceiver: the event receiver that should be registered.

ResetProbingClone  protected override

Resets channel that is used for probing

procedure ResetProbingClone(aProbe: TROTransportChannel)

Parameters:

  • aProbe: Probing clone

RetrieveMetadata  protected virtual    (declared in TROTransportChannel)

Returns server-side RODL.

procedure RetrieveMetadata(out Dest: TStream)

Parameters:

  • Dest: Stream

RetrieveResponse  protected

Indicates whether an answer is received after an InvokeRequest.

procedure RetrieveResponse(const aMessageID: string; aResponse: TStream)

Parameters:

  • aMessageID: Id of a waiting response
  • aResponse: Response data

RetrieveRODL  protected    (declared in TROTransportChannel)

This method is used for to obtaining the RODL library from the server without havin to rely on a channel-specific mechanism (such as a HTTP request to http://servername:port/rodl).

procedure RetrieveRODL(out RODLLibrary: TRODLLibrary)

Parameters:

  • RODLLibrary: Result

ReturnChannelToPool  protected virtual    (declared in TROTransportChannel)

procedure ReturnChannelToPool(aChannel: TROTransportChannel)

Parameters:

  • aChannel:

ROActiveAsyncTransportChannel_InvokeRequest (TStream, Boolean, TROEvent): string  protected overload virtual abstract

function ROActiveAsyncTransportChannel_InvokeRequest(aRequest: TStream; aGetResponse: Boolean; aEvent: TROEvent): string

Parameters:

  • aRequest:
  • aGetResponse:
  • aEvent:

ROFreeNotification    (declared in TROComponent)

Forwards notification messages to all owned components.

procedure ROFreeNotification(aComponent: TComponent)

Parameters:

  • aComponent: component

RORemoveFreeNotification    (declared in TROComponent)

Forwards notification messages to all owned components.

procedure RORemoveFreeNotification(aComponent: TComponent)

Parameters:

  • aComponent: component

SendRemoveNotification  protected    (declared in TROComponent)

Forwards notification messages to all owned components.

procedure SendRemoveNotification(aComponent: TComponent)

Parameters:

  • aComponent: component

SetAsyncBusy  protected override

procedure SetAsyncBusy(const Value: Boolean)

Parameters:

  • Value:

SetConnectedState  protected

procedure SetConnectedState

SetInactive  protected virtual

procedure SetInactive

SetServerLocator  protected    (declared in TROTransportChannel)

Retrieves the location details of a server from aServerLocator.

procedure SetServerLocator(aServerLocator: TROServerLocator; anException: Exception)

Parameters:

  • aServerLocator: Configuration data of the server
  • anException: Exception

SuperChannel_RaiseError  protected virtual abstract

procedure SuperChannel_RaiseError(aCode: Integer)

Parameters:

  • aCode:

TerminateWorkerThread  protected

procedure TerminateWorkerThread

TriggerProgress  protected override

Fires OnProgress event

procedure TriggerProgress(aType: TProgressType; aDirection: TProgressDirection; aTransfered: Integer; aTotal: Integer)

Parameters:

  • aType: progress type
  • aDirection: direction
  • aTransfered: transfered bytes
  • aTotal: total bytes

UnregisterEventReceiver  protected virtual    (declared in TROBaseActiveEventChannel)

Unregisters the specified IROEventReceiver aReceiver in the specified channel.

procedure UnregisterEventReceiver(aReceiver: IROEventReceiver)

Parameters:

  • aReceiver: The event receiver that should be unregistered.

UnregisterEventReceivers  protected    (declared in TROBaseActiveEventChannel)

Unregisters the all event receivers in the specified channel.

procedure UnregisterEventReceivers

WaitForActive

procedure WaitForActive(const aTimeout: Integer)

Parameters:

  • aTimeout:

 

ConnectEvent

property ConnectEvent: TROEvent read

OnAfterEncrypt    (declared in TROBaseConnection)

Fired after stream was encrypted

property OnAfterEncrypt: TROBaseConnectionOperation read write
delegate: procedure OnAfterEncrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnAsyncException    (declared in TROTransportChannel)

Fires when exception is raised in asynchronous mode

property OnAsyncException: TROAsyncExceptionEvent read write
delegate: procedure OnAsyncException(Sender: TROTransportChannel; Async: IROAsyncInterface; anException: Exception)

OnBeforeDecrypt    (declared in TROBaseConnection)

Fired before stream will be decrypted

property OnBeforeDecrypt: TROBaseConnectionOperation read write
delegate: procedure OnBeforeDecrypt(Sender: TROBaseConnection; aEncryptedStream: TStream)

OnConnected

Fires when channel is connected to server

property OnConnected: TNotifyEvent read write

OnDisconnected

Fires when the active connection to the server has been dropped or lost.

property OnDisconnected: TNotifyEvent read write

OnException    (declared in TROTransportChannel)

Fires if an exception is raised during the execution of a remote request. This could be an exception returned from the server, a communication problem or an error within the client. Depending on the type of error, your event handler can try to rectify the problem, and set aRetry to true to have the channel try and perform the request again. For example, an application could show a dialog asking the user to confirm if his internet connection is available, with Cancel and Retry buttons.
If aRetry is set to true and the call succeeds at the second attempt, the call will return to the original code that initiated the request, as if the exception never happened.

property OnException: TROExceptionEvent read write
delegate: procedure OnException(Sender: TROTransportChannel; anException: Exception; var aRetry: Boolean)

ReconnectEvent

property ReconnectEvent: TROEvent read